240 THOUGHTS ON BELIEF AND EVIDENCE. 



on states of the brain, and it is a grand general law that simultaneous 

 or imnieiHately successive states become sympathetically connected ; 

 so that the recurrence of the one, whether as a sensation or its cor- 

 responding idea, brings up the idea or thought of the other, the 

 connection becoming stronger and more certain by every repetition. 

 Accordingly, when certain changes have recurred again and again, the 

 one following the other, the presence of the antecedent uniformly 

 suggests the idea of the consequent, and this thought of it as about 

 to come constitutes our belief or expectation. Every observed case 

 of uniform sequence has the same character, and generalizing, we 

 obtain the ideas of the relation of cause and effect and of power in 

 the antecedent to produce the consequent — this latter abstraction 

 being only our feeling of the certainty with which the consequent 

 follows. The whole is a case of invariable association creating irre- 

 sistible and steady expectation. When we reason backwards from 

 the effect to the necessity of a cause, we only apply to a partially 

 known particular case a general law derived from all known cases. 

 It has been maintained that, according to this view, the necessity for 

 a cause exists only in our minds, not in the nature of things, and, 

 however strongly felt by us, has no real existence. The reply is, that 

 philosophy knows of no greater force of conviction than invariable 

 association of certain ideas, and that where the laws of our nature 

 compel belief it is madness to demand, different or stronger grounds 

 for it. The very simplicity of the cause of our belief in effects fol'- 

 lowing their causes, is what has given occasion to its being described 

 as instinctive, and it is so truly, if that term be assumed to mean 

 only that it is an invariable result of our nature. In this case there 

 is no act or state of belief different from the presence of an idea.- 

 which is raised according to a uniform law. 



I pass to the investigation of belief in a scientific generalization. 

 This is a sort of proposition affirming some definite relation between 

 the objects or ideas expressed by or contained in the subject, and the 

 objects, qualities, or ideas included in the predicate. It can have no 

 meaning if the proper extent and limits of the terms be not clearly 

 understood. This being so, it contains an intelligible proposition, 

 and the question arisps : Why we believe it ? The case is one in 

 which a great many believe on authority merely. Science offers its 

 truths for the guidance of practical men, who receive them as coming 

 from those who know, and as being established to the satisfaction of; 



